The present invention relates to an improvement in valve units used in the piping of a split type of air-conditioner suitable for a residential chamber.
Such an air-conditioner comprises an indoor unit and an outdoor unit interconnected by a high-pressure-side pipe and a low-pressure-side pipe. Three-way valves are normally used, as shown in FIG. 6A, to connect a high-pressure-side conduit l.sub.1 and a low-pressure-side conduit l.sub.2 extending from a heat exchanger b.sub.1 of the indoor unit a.sub.1, to a heat exchanger b.sub.2 or a compressor c of the outdoor unit a.sub.2, to install the air conditioner; and this is used in the operation of the compressor to charge refrigerant and also to recover refrigerant from the indoor unit a.sub.1 into the outdoor unit a.sub.2 for the purpose of repositioning the air conditioner.
The conventional three-way valve v, shown in FIG. 6B, comprises an upper body 1 and a lower body 2. The upper body 1 includes a valve rod holder 1a having a longitudinal bore with internal threads, a sub-adapter 1c having a lateral through-hole as a charging inlet for refrigerant, and a main adapter 1b having a lateral through-hole which communicates through an enlarged chamber 1d with the other lateral through-hole in a different level. The lower body 2 is in a cock-like form and provided with a longitudinal bore in alignment with the longitudinal bore in the holder 1a and the enlarged chamber 1d, and a lateral bore into which a short pipe 2a is fitted for connection to the compressor. A valve rod 3 is threadedly received into the holder 1a and is provided at its lower end with a valve element 3a which has the shape of two truncated cones and is positioned in the enlarged chamber 1d. The holder 1a and the sub-adapter 1c are covered by caps 4a and 4b, respectively.
When the air conditioner is in operation, the valve rod 3 is moved upwards to shut off the longitudinal bore in the upper body by engagement with the upper surface of the valve element 3a; and, when the air conditioner is being transported, the valve rod 3 is moved downwards to shut off the longitudinal bore in the lower body 2 by engagement with the lower surface of the valve element 3a.
As described above, since the conventional three-way valve uses a method of switching refrigerant passages in the middle of the body of the valve unit by engagement of the upper and lower surfaces of the valve element therewith, an enlarged chamber is required for the valve. Accordingly, for technical reasons, the body of the valve unit must be constituted by two separate parts, that is, the upper and lower bodies 1 and 2 instead of one continuous body and is constructed such that after the valve rod 3 is fitted into the upper body 1 and the head portion of the lower body 2 is inserted into an opening of the upper body 1, the junction between these two bodies is brazed and then washed. This process is labor-consuming and expensive, and sometimes results in a misalignment of the longitudinal bores in the upper and lower bodies 1 and 2 which makes the valve element 3a malfunction in the partitioning thereof. Additionally, the manifold-like upper body 1 and the cock-like lower body 2 are mainly formed in a rather inefficient forging manner, because the cutting of such parts would waste a considerable amount of material. This also results in increased cost of manufacturing the body of the valve unit of this kind.